(A) Morphology of nuclear donor fetal fibroblasts before SCNT. (B) Poor-quality human SCNT blastocyst without distinct ICM produced with suboptimal protocols; note the presence of excluded cells.
(C) Spindle-like structures detected when donor nuclei were introduced into intact MII oocytes, but not when introduction was conducted after enucleation. Arrowhead and arrow point at the maternal MII spindle and somatic cell spindle, respectively.
(D) Somatic nuclear cell spindles were formed in cytoplasts when oocyte enucleation and fusion were conducted in the presence of caffeine.
(E) Human SCNT blastocyst with prominent ICM (asterisk) produced after caffeine treatment.
(F) NT-ESC colony with typical morphology derived from a caffeine-treated SCNT human blastocyst.